The purpose of the Master Phase II Rolling Arm Master Protocol (PRAM) is to evaluate a series of novel combinations of antiretroviral gents with respect to the change in plasma HIV-1 RNA copy number from baseline to 48 weeks in stable HIV-infected children >16 weeks of prior continuous antiretroviral therapy. The purpose of the PRAM-1 study is to evaluate the previously mentioned treatment regimens, specifically using ZDV+3TCTM vs. d4T+Ritonavir vs. ZDV+3TCTM+Ritonavir as the novel treatment combinations.